Chip64 is digital HAM radio transmission mode developed by me (Nino Porcino, IZ8BLY) and Murray Greenman, ZL1BPU in 2004.
It uses a direct-sequence-spread-spectrum modulation technology (DSSS) restricted to the narrow bandwidth of HAM radio channels.
Published here on GitHub is the software I used to develop the mode and that later was distribuited to the radio amateurs community to be used in real QSOs. Included is the verbatim copy of the first contact done on the 20m band and logged by the program.
I publish the source code here on GitHub to prevent it from disappearing into oblivion (the code itself survived a severe disk crash occurred in 2008).
The software was written in C++ using the Borland C++ Builder (v6) and may be used under the terms of the GNU Public License.
It contains code (the Viterbi decoder) from Phil Karn KA9Q which is also GNU public licensed.
The executable can be downloaded from the Chip64 web page.
If you have any questions you can write me at: iz8bly (at) yahoo.it.
Enjoy,
-Nino